Exposure to water, ultraviolet radiation, ozone, and other noxious factors can cause the unprotected surfaces of, for example, automobiles, various other vehicles, aircraft, bridges, buildings, etc., to suffer from timewise changes in quality (deterioration). This has led to the introduction of a large number of coating materials for the purpose of surface protection. Among the spectrum of coating materials, those based on acrylic resins are reported to have excellent resistance to weathering. Even in the case of acrylic resin coating materials, however, long-term exposure to such challenges as wind and rain and ultraviolet radiation still leads to degeneration and a concomitant decline in gloss, water repellency, and the protective film properties that were the initial reason for applying the coating.
As examples within the realm of coating materials that employ an organosilane or organopolysiloxane starting material, Japanese Application Number Sho 57-36109 teaches a coating material comprising a copolymer of .gamma.-methacryloxypropyltrimethoxysilane and acrylic monomer, while Japanese Application Number Hei 9-279064 teaches a coating material based on a copolymer of acrylic monomer and linear alkylpolysiloxane bearing the methacryloxy group at a single terminal. These coating materials, however, have suffered from such problems as a low film strength and an unacceptable water repellency and particularly an unacceptable water-repellency retention.
The object of this invention is to solve the problems described above by providing a highly weathering-resistant coating material that in particular has an excellent gloss retention and water-repellency retention.